Improve type-inference in LowRankOperator bandwidth (#442)

Author: jishnub

src/Operators/almostbanded/LowRankOperator.jl

@@ -42,10 +42,9 @@ function convert(::Type{Operator{T}},L::LowRankOperator{S}) where {S,T}
 end
 
 
-datasize(L::LowRankOperator,k) =
-    k==1 ? mapreduce(ncoefficients,max,L.U) : mapreduce(a -> bandwidth(a,1) + bandwidth(a,2)+1,max,L.V)
-datasize(L::LowRankOperator) = datasize(L,1),datasize(L,2)
-bandwidths(L::LowRankOperator) = datasize(L,1)-1,datasize(L,2)-1
+datasize(L::LowRankOperator,k) = datasize(L)[k]
+datasize(L::LowRankOperator) = (mapreduce(ncoefficients,max,L.U), mapreduce(a -> bandwidth(a,1) + bandwidth(a,2)+1,max,L.V))
+bandwidths(L::LowRankOperator) = datasize(L) .- 1
 
 domainspace(L::LowRankOperator) = domainspace(first(L.V))
 rangespace(L::LowRankOperator) = space(first(L.U))